V.I. IVASHCHENKO (IG KarRC RAS), K.A. KONEVIN (OOO «Industriya»)

Noble metal mineralization of Motko and Kuolisma Proterozoic gabbrodolerite intrusions (Karelia)

Results of studies of Proterozoic gabbrodolerite intrusions of Motko (2274±3 Ma) and Kuolisma (1960±2 Ma) in Central Karelia are reported. A brief description of their geological structure, degree of differentiation and rock composition is given. It is shown that noble metal mineralization is spatially combined with titanomagnetite horizon and associated with the formation of copper­sulfide mineralization. Platinum group metal minerals are mainly represented by palladium and platinum bismuthotellurids, arsenids and stibioarsenids with kotulskite and sperrylite being dominant. Chalkopyrite, bornite and chlorine­containing (up to 5.5%) ferrogastingsite are indicator minerals of noble metal mineralization. Ore occurrences can be economically significant after additional appraisal.
Keywords: Karelia, Proterozoic, gabbrodolerite magmatism, Fe­-Ti-­V­-PGE­-Au mineralization, ore indicator minerals, Cl­amphibole, fayalite.